NOBREGA, P. S. B.; http://lattes.cnpq.br/4578297352391137; NOBREGA, Priscila de Sousa Bezerra.
Résumé:
The fast industrial development and the increased concern about environment
require industries seek faster chemicals processes without higher costs,
efficient and do not harm the environment. Thus, catalysis, through the catalyst
came to accelerate chemical reactions providing agility in chemical processes,
low waste production, reducing the amount of raw material and energy costs for
obtaining the expected product. The silicoaluminophosphates (SAPO's) are
molecular sieves that generate great interest for their potential industry
applicability. The SAPO-5 is a member of the family of silicoaluminophosphates,
is a microporous material with large pore and possess a variable silicon content,
therefore a mild acidity. It can be used as catalyst and as a supported metal
catalyst, generating interest for their properties similar to those of zeolites. The
SAPO-5 was used as metal support. The SAPO-5 support was synthesized by
biphasic hydrothermal method. The combination of metals selected for the
formation of the catalyst, expressed as oxides, was NiO - W03 . A series of
catalysts NiW supported on SAPO-5, compositions with 5, 10 and 15 wt.% of
W03 e 2 wt.% of NiO, were prepared by sequential incipient wetness
impregnation of the materials with aqueous solution of Ni(N03)2.6H20 and
H2W04 . The support and catalysts were analyzed by several techniques such
as: XRD, EDX, SEM, FTIR, TG and BET. The results obtained by
characterization indicated that crystalline SAPO-5 was obtained and after its
calcination the material was more organized than before, what indicate better
crystallinity. The XRD of NiW catalysts showed a decrease of the characteristics
peaks of SAPO-5, it was found by SEM agglomerates impregnated oxides. The
EDX revealed that the Si02 decrease considerably with increasing contente of
W03 . The BET sample showed a decrease in pore volume and in pore diameter
by impregnation of NiO and W03 . The SAPO-5/NiW catalyst had its surface
properties affected by impregnation as expected.